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In the era of aging of European society, there is a need to rationalize public expenditures. As a result, it is crucial to increase the efficiency of public policy. It significantly refers to labor market policy, as on the one hand, it is responsible for activation of the unemployed, passive resources, increasing employability and optimal usage of labor supply. On the other hand, public entities conducting labor market policy (mainly public employment services—hereafter PES) are obliged to efficient management of public funds. The effectiveness of PES is strongly determined by the engagement of employers in realization of labor market instruments. Cooperation of PES with relevant stakeholders is needed to build up alliances for active policy. There are different models of such cooperation, with variant levels of partnership, communication channels, and mutual services. The main objective of the article is to determine the perspective cooperation model of PES and private companies in Poland. The quantitative study was realized among large companies in Podlaskie province. It is one of the Polish peripheral regions characterized by lower than average labor demand, lower purchasing power, and higher unemployment rate.

To review the current state of resources and environmental sciences in China, this study assessed highly cited papers of five leading CSSCI journals sourced from the Chinese National Knowledge Infrastructure database. The fields of resources and environmental sciences were the research focus, and the bibliometric analysis software CiteSpace was used to perform co-occurrence analysis on keywords, authors, and research institutions based on bibliometrics and social network analysis. Furthermore, the research hotspots, scientist groups, and main cooperation models in the field of resources and environmental sciences in China were also explored. The results show that: (1) For 30 years, the interdisciplinarity of resources and environmental sciences has become more and more intense, and research themes have become increasingly extensive. The research hotspots of highly cited papers focused on energy, ecology, land, water resources, and sustainable development. In recent years, problems associated with energy and carbon emissions have aroused great interest. The ecological and sustainable development of resources and environmental elements has emerged as a future research trend. (2) An analysis of scientist-oriented networks shows that highly cited papers are mostly published by group authors. Scientists work closely within their respective academic groups, while intergroup academic cooperation is rare. Furthermore, connectedness between cooperation networks is poor, and scientists are largely connected through their research institutions. Cooperation among scientists is greatly affected by their geographical locations. Research institutions in the same region are more likely to cooperate. Beijing and Nanjing are high-producing areas of highly cited papers. The Institute of Geographic Sciences and Resources, CAS, is the most influential research institution. This paper introduces the state-of-the-art research hotspots of Chinese resources and environmental sciences to international academic circles and provides a basis for the research practice of resources and environmental sciences worldwide.

The Silk Road Economic Belt and 21st Century Maritime Silk Route established China’s new external strategy basis for the near-term historical perspective. The implementation of these projects, which were united under the common name “One belt, one road”, will become one of the most important tasks of Beijing to optimize the spatial structure of the entire Eurasian region economic development. Russia and Central Asian countries take a prominent place in the process of implementing this initiative. China actively cooperates with these countries. All parties receive great benefi ts of this comprehensive cooperation. The purpose of this article is to determine the role of Russia and Central Asian countries in the implementation of the Chinese initiative “One belt, one road”. In accordance with the purpose, the following tasks were set: to study the main types and directions of China’s cooperation with Russia and the Central Asian republics within the framework of the initiative, to analyze the specifi cs of this cooperation, and to consider the aspects of interaction between the parties. The problem-chronological approach was used as a methodological basis, it allows to study certain aspects of interaction, international relations subjects. Based on the results of the analysis, the author concludes that Russia and the Central Asian republics take a key place in the implementation of the Chinese initiative “One belt, one road”.

There are few publications on the subject of business models open to innovations in Poland, especially relating to cases of their practical application. The article analyses various types of open innovations and the possibility of using them in the conditions of the Polish agricultural market. After reviewing the literature, analysing cases of chemical companies, conducting interviews with members of the Grupa Azoty Pulawy consortium, the author proposes a model of cooperation platform for entities from various sectors that systemically combines open inbound and outbound innovations with the requirements of the business model.

Non-compliance with requests from the International Criminal Court (ICC) for cooperation — mainly arrest warrants and orders for surrender of persons — appears to be an increasing concern. The author illustrates the cooperation model underlying the ICC Statute and highlights the limitations of what he describes as the ‘harmony approach’ which the drafters had in mind. He then shows a number of perplexing issues in the Court’s case law on non-compliance, and emphasizes distinctions to be made between political, administrative and judicial aspects of non-cooperation proceedings. Finally, he argues in favour of a more robust role for the Assembly of States Parties (ASP) and suggests a system of reactions to non-cooperation which the ASP should adopt.

The United Nations and organized civil society in the form of international NGOs have yet to find an optimal mode of engagement that works for both sides. This has many reasons, but foremost it is caused by a formalized and politicized administrative process with, in the end, rather limited participation opportunities for NGOs. The current regime fails to live up to its potential – a deficit that is becoming more acute as both the UN and NGOs face legitimacy pressures and have to brave geopolitical and resource uncertainties. In response, the article proposes a more differentiated cooperation model based on functional roles and new organizational formats. Such an approach could enable a mutually beneficial relationship to emerge between the United Nations system and international civil society.

An effective ship scheduling strategy is critical for the efficiency of waterway transportation, especially in restricted one-way waterways. By treating ship traffic as a distributed system, a novel Ship Self-Organizing Cooperation algorithm (SSOCA) is proposed to evaluate the effects of self-organizing cooperation between ships. An assumption is made that overtaking is not allowed under the given safety requirement. Observing that traffic efficiency is influenced by speed differences, two types of delay times, wait time and navigation time as increased by speed reductions, are applied to evaluate traffic efficiency. The mathematical model of delay time is inferred in different entry sequences subsequently. Taking advantage of the delay model, each ship makes a decision regarding its own sequence to find the local optimum iteratively. An Arena-based ship traffic model is constructed. The simulation results indicate that average delay time for ships is decreased in comparison with the First Come First Served (FCFS) model. That advantage exists for different combinations of traffic flow parameters. Moreover, a balance between efficiency and computation is also achieved by distributing the computational burden to each ship.

In this paper, a cooperation model between a generating company and several marketers is presented. The model considers two cooperation schemes. The first finds the optimal decision for the generating company and the group of marketers in terms of maximization of their profits, based on bi-level optimization. Second scheme proposes the cooperation among the marketers, whose objective is to serve a common set of consumers and to increase their profits through cooperation, with respect to the profit gained individually. Profit of the marketers group are divided among them, based on the Shapley value. The model was solved using GAMS and Visual Studio Tools for Office and was validated through a case study in a region in Colombia. The results of the study showed that implementing these cooperation structures brings additional economic benefits to the cooperating agents. Keywords: Cooperation models, Energy market, Bi-level optimization, Shapley value

This paper is concerned with the forced traveling wave solution of a nonlocal dispersal Lotka-Volterra cooperation model under the habitat shifting with a constant speed. Particularly, we relax the condition of intrinsic production so that there may be no sign change. By constructing a pair of upper and lower solutions and using the method of monotone iteration, we prove the existence of traveling wave solution for any positive constant shifting speed.

In Computer, Communications and Consumer-Electronics (3C) industries, manufacturers must provide the exact predicted demand or number of contracts with brand manufacturers so that distributors can prepare the correct inventory. Moreover, manufacturers are obligated to provide weekly or monthly production capacity and components consumption to distributors in order to facilitate distributor deliveries for timely stocking to maintain the right amount of inventory within Hub warehouses. Thus, the establishment of a consignment cooperation model is very important. This study considered the estimated proportion of profits assigned to distributors under the leadership of the manufacturers and established and analyzed the mathematical model of the final product unit sales prices, as well as the final product unit production cost using global search particle swarm optimization (PSO). According to the analysis results, the proportion of profits assigned to distributors is not necessarily higher when the product unit sales volume is higher; for distributors, more components in stock naturally raise the cost. The consignment cooperation model helps increase the profits of the manufacturer. It is expected that the establishment and analysis of the model proposed herein can provide manufacturers in the 3C industries with decision-making suggestions.

StreszczeniePraca ma na celu identyfikację modelu odwzorowującego efektywne współdziałanie w pozycjonowaniu gry (przyjęciu zagrywki – podaniu) w piłce siatkowej. W pracy wykorzystano oryginalną metodę badawczą zwaną pragmatycznym studium unikatowych przypadków. Badania obejmują obserwację zespołu narodowego Stanów Zjednoczonych w grze podczas Igrzysk Olimpijskich w Rio de Janeiro 2016. Na podstawie obserwacji oraz wykorzystania autorskiego arkusza obserwacji przyjęcia zagrywki udało się zidentyfikować pewien model odwzorowujący efektywne współdziałanie w przyjęciu-podaniu zagrywki, oparty o kryterium dokładności współdziałania oraz elastyczności współdziałania. Na podstawie badań można też stwierdzić, że istnieją różne modele współdziałania w tym elemencie, które stosują drużyny o największej efektywności sportowej. Modele te różnią się od siebie. Praca ta skłania do przemyśleń na temat identyfikowania współdziałania w grach zespołowych i zachęca do prowadzenia dalszych badań w tym temacie. AbstractPurpose: The paper is aimed at identification of a model which shows the effective cooperation in the game positioning (exactly in receiving-passing the ball) in a volleyball game.Design/methodology/approach: The original research method is used in this thesis which is called pragmatic unique case study. The research is aimed at observation USA team playing volleyball during The Olympic Games in Rio de Janeiro 2016. Findings: There is a cooperation model in receiving and passing the ball among USA volleyball team players found, based on the observation. There are also other cooperation models used by teams. Research and practical limitations/implications: Based in the research I can tell that there are different models of cooperation in the game positioning in volleyball. The teams which are the most effective use different models of cooperation while playing. Originality/value: The paper is original and leads to think about the identification of the process of cooperation in team games. More research in this field is recommended.

This paper is concerned with a competition and cooperation model of two enterprises with multiple delays and feedback controls. With the aid of the difference inequality theory, we have obtained some sufficient conditions which guarantee the permanence of the model. Under a suitable condition, we prove that the system has global stable periodic solution. The paper ends with brief conclusions.

In the limited rational decision-making activities of enterprises, there are both competition and cooperation among all kinds of enterprises in the logistics park. Based on the theory of co-evolution, using the principle of biological immunity and combining with logistic model, this paper constructs a co-competition and co-evolution model of logistics park enterprises based on immune mechanism. The simulation model is established by using the Matlab simulation platform, and the model is run under the conditions of competing parameters of different enterprises. It shows the change mechanism of population density in the process of competitive and cooperative co-evolution, and provides a reference theoretical basis for enterprises in logistics parks to formulate effective competitive and cooperative strategies. Besides, the application of immune theory in the construction of enterprise competitive and cooperative co-evolution model, provides a new perspective and method for the study of cooperative and cooperative co-evolution behavior of enterprises in logistics parks.

Investment on product greenness in green supply chain is always restricted by the emerging supplier&rsquo, financial constraints, so manufacturers always share the suppliers&rsquo, investment to encourage the suppliers&rsquo, green innovation. Based on the two-stage cooperation model between one manufacturer and one emerging supplier, and the assumption that emerging suppliers need to reach a certain survival threshold at the end of each period, this paper studies investment on product greenness and sustainability of cooperation in the supply chain. The impacts of consumers&rsquo, preference for greenness (CPG), market volatility, financial constraints, and investment-sharing proportion are also examined. It was found that when market volatility and CPG exist at the same time, compared with the deterministic environment, emerging suppliers will improve (or reduce) the wholesale price and greenness at the same time to balance the short-term bankruptcy risk and the long-term profit, and suppliers&rsquo, green investment would be stimulated by the increasing demand uncertainty. Besides, when suppliers&rsquo, financial constraints increase, manufacturers will also increase its sharing proportion of green investment. Lastly, there always exists an investment-sharing proportion that optimizes the sustainability of cooperation and profits jointly.

The triple helix (university-industry-government) is a dynamic cooperation model in the area of regional innovation. With the application of this model, the authors aim to address the mechanism of how multiple participants affect innovation efficiency against the research background of China Fuzzy-Set Qualitative Comparative Analysis (fs-QCA) is applied to conduct a multiple-case analysis. With the evaluation of 31 provinces in China, which have various innovation performances and degrees of regional cooperation, the authors find strong evidence to support the positive effects of multiple participants on regional radical innovation. Moreover, this article also finds two typical configurations of factors that contribute to high innovation efficiency. Based on the results, the authors propose policy implications to improve China&rsquo, s regional innovation in different areas. Finally, this paper concludes with the discussion of future research orientations, which could focus on the differences in the triple helix among different industries in China.

This study discusses the cooperation model between the small and major scenic spots in peak seasons of tourism. First, we create a tourism supply chain that contains only one major and one small scenic spots to divert some tourists to a nearby scenic spot, reduce large scenic spot pressure, increase the benefits of small scenic spots, and promote the healthy development of the tourism supply chain. Second, we build two cooperation models between the major and the small scenic spots: the revenue-sharing model and the cost-sharing model. Based on a numerical analysis, we give a more clear comparison about the revenue changes and the overall efficiency changes of the tourism supply chain in these two models. Our results confirm that the cost-sharing model is an ideal cooperation model. In the cost-sharing model, the two parties’ revenues in the tourism supply chain are better than those in the revenue-sharing model, and the entire supply chain efficiency could be improved.

This research is to analyse the existing cooperation between universities and the construction industry and to investigate what is the most effective model for long-term cooperation between an academic university and the private construction sector. The current article describes the human resources management tools to be used by employers to create interrelations between the paid salaries and productivity, thus providing both individual and corporate results. The suggested different tools contribute to keeping employees satisfied and motivated, simultaneously properly balancing productivity and individual earnings. The researchers conclude that it is necessary to create a new model for personnel selection and a new approach to stimulate motivation and maintenance within the construction industry. In order to respond to the needs of the sector for professionals and the required increase of the qualifications of the mentioned specialists, it is necessary that the country improves the level of education of the future professionals for the construction industry and changes the system of testing their professional qualifications, which means cooperation between the educational institutions and the industry. The suggested cooperation model by authors may provide a general guideline for further detailed researches and its implementation may help similar-sized economies to make possible national adjustments. The implementation of this model in bigger and/or developed economies should be justified by separate additional research.

University-enterprise Cooperation Model is very important in Talent Training for local undergraduate universities. This paper designs a survey outline, which is mainly for students of the university-enterprise cooperation class. According to the results of this survey, the teaching of University-enterprise Cooperation Model promotes reform of classroom teaching and strengthen the link of practical teaching, enriches the University’s teaching resources, and improves students’ practical application abilities. But still it shows some problems to solve, such as there should be more explicit standard for training students’ application abilities during teaching, relevancy between thesis and actual enterprise issues shall be improved and students’ application abilities shall be constantly strengthened, teachers’ practical teaching abilities shall be strengthened and a team of “double-position and double-capacity” teachers shall be built.

The “Ice Silk Road” has been included in the overall layout of the “Belt and Road” and is also an innovative cooperation model and cooperation concept of the “Belt and Road Initiative” initiative. The "Ice Silk Road" is a new achievement in the development cooperation between China and Russia in recent years, which fully reflects the spirit of cooperation and openness. With the positive response of more and more countries, its smooth progress will have a far-reaching positive impact on the sustainable development of the world economy, the regional economic balance and China's foreign strategic cooperation, and provide opportunities for its development. However, the “Ice Road on Ice” also faces challenges in geopolitics, traditional trade routes and ecological environment. As the main advocate and important participant of the “Ice Silk Road”, China must fully tap the opportunities and potentials, correctly respond to various challenges, and propose corresponding solutions.

In this chapter, we engage with subnational cultural relations, with a focus on international and interregional relations. After acknowledging the conceptual challenge that international subnational relationships represent for disciplines like Political Science, International Affairs, and many other cognate fields, we discuss different cases that result from the institutional complexity of federations. This chapter focuses on three types of international relations developed below the national levels in federations, namely: the agent-general model, the affirmative model, and multilateral and multilevel cooperation model.

This paper mainly discusses three issues from the perspective of geo-economics: First, discuss the two arguments of “the transfer of world economic centers” and the “counterbalancing China’s increasing geo-presence” through comparing the economic development dynamics of “Indo-Pacific” and “Asia-Pacific” and analyzing the economic interaction between the two regions; second, provide evidences that containing China with “Indo-Pacific” strategy may impede regional economic development by analyzing the periodic changes of the “Indo-Pacific” geo-economic pattern and comparing the influence and contribution of “Indo-Pacific” strategic partners (the U.S., Japan, Australia and India) and their balancing object (China); third, put forward some thoughts on strengthening the geo-economic cooperation in the “Indo-Pacific” region by comparing the economic inputs of China, the U.S., Japan, Australia and India in the “Indo-Pacific” region and analyzing their different attitudes towards the “Indo-Pacific” strategy. The main conclusions are that: first, despite no obvious transfer trend of the world economic center, the increased dependence of the “Asia-Pacific” region on the “Indo-Pacific” region enhances the geo-economic importance of the latter; second, the origin of the “Indo-Pacific” concept is resulted from not only the geo-economics itself but also the realistic or perceived threat on the U.S., Japan, Australia and India caused by China’s development model successfully driven by the geo-economics; third, as China has surpassed and become the leading force and defender in the regional economic cooperation years ago, the U.S., Japan, Australia and India are the challengers to the current order of the geo-economic pattern; fourth, the “Indo-Pacific” region is more important to the geo-economics of China, Japan, Australia and India than that to the U.S.; fifth, if the “Indo-Pacific” strategy attempts to contain China, it will inevitably lead to the tearing of geopolitics and geo-economics, and then damage the economic growth and integration of the region; sixth, China shall pay attention to the strategic direction of the “Indo-Pacific” strategy, seek the converging points of common interests with other countries, and dissolve the adverse factors. Meanwhile, efforts shall also be made to continuously drive a more open and inclusive geo-economic cooperation model.

[EN] The cooperation between China and Venezuela is both strategic and complementary in nature, and has characteristics of a complex interdependency built on oil supply as the main axis and the ‘Loans for Oil’ model as a key dynamic background. With the oil price slump, China’s commercial presence in Venezuela is now faced with the potential risks of debt default, geopolitical unrest and possible u.s. interference. This article explores the trajectory, modalities, dynamics and risks of the China-Venezuela cooperation model through a Chinese perspective, which is regarded as a typical model of the South-South cooperation paradigm. La cooperación entre China y Venezuela es estratégica, altamente complementaria y tiene características de una interdependencia compleja, construida a base de la provisión petrolera como eje principal y el modelo «préstamo por petróleo» como dinámica clave de fondo. Con la caída del precio petrolero, la presencia china en Venezuela está afrontando riesgos potenciales de incumplimiento, de inestabilidad geopolítica e, incluso, la posibilidad de una intervención norteamericana. Este artículo explora la trayectoria, modalidades, dinámicas y riesgos de la cooperación sino-venezolana desde una perspectiva china, la cual se considera como un típico modelo del paradigma de la cooperación Sur-Sur.

Durch die Konsolidierung des Sendungsvolumens von kooperierenden Baustoff-Fachhändlern wird die Verbesserung des Logistiknetzwerks angestrebt, um somit die Transporteffizienz der Kooperationspartner zu erhöhen. Zusätzlich zur Entwicklung des Kooperationsmodells wird dieses durch Simulationen anhand von Realdaten evaluiert und die Auswirkung des Kooperationsmodells auf die zu fahrende Gesamtstrecke der Kooperationspartner untersucht.

This article aims to verify to what extent the Students-Graduate Agreement Program can be considered as a program that meets the principles of South-South Cooperation. To this end, we sought to further investigate the positioning of Brazilian foreign policy at the time the program was conceived, then we sought to understand the real reasons that led to the creation of the PEC-PG and, finally, we sought to investigate the conception South-South Cooperation Program and observe the extent to which it distances itself from the common cooperation model and find out if the Graduation Agreement Students Program - PEC-PG could be considered a cooperation program that meets the principles that guide South-South cooperation. The development of the work took place through documentary searches, periodicals, theses and books, the paradigm adopted was the interpretative one, since the subject sees the social world in the form of a social process created by the individuals involved. As final considerations, it was possible to observe that the PEC-PG was created with the intention of helping the national economic development of the time and that, although it is a cooperation program between the countries of the South, it cannot be characterized as a program that meets the principles of cooperation South-South, as some of the program's prerogatives differ from the one proposed by the CSS.

We introduce a novel framework for analyzing coalition formation, applied to climate cooperation. Our model allows for multiple rounds of negotiations and is able to explain the formation of large coalitions. The incentive of each coalition member to join and subsequently to sign a long-term contract is to prevent inefficient delay that arises as soon as a single country deviates. This undermines the free-rider incentive that destabilizes large coalitions in static coalition formation games. The equilibrium coalition size is then determined by a “threshold effect” due to which deviations of coalition members become unprofitable for sufficiently large coalitions.

Under the new situation, the cultivation of high-level professional postgraduates with both innovative and practical ability has become a key issue to be solved urgently in current graduate education. Professional postgraduates are different from academic postgraduates, and their training methods should also be different from academic postgraduates. This research analyzes the reasons for the problems and shortcomings of the current professional postgraduates training model in the school-enterprise cooperation model, and provides a new and effective training model for professional postgraduates school-enterprise cooperation based on engineering projects. Based on the vision of collaborative innovation and collaborative training, this study summarizes the practical problems and international experience of the training mode of professional postgraduate. Relying on the existing engineering conditions and practice environment of disciplines, schools and cooperation units, through the establishment of school enterprise collaborative innovation group, this paper puts forward the school enterprise collaborative training mode of professional postgraduate with engineering project as the carrier, from three aspects of adhering to the engineering project as the carrier, adhering to the interactive training process, and adhering to the team collaborative training research, social services and other integrated cooperation framework provide macro response ideas, micro solutions and operational implementation path for collaborative innovation training. Through the clear school enterprise cooperation project, this new training effectively collects the resources and elements of universities and enterprises, and realizes the effective collaboration of school enterprise cooperation in cultivating applied innovative talents.

This article places sharing forensic biometric data for international criminal justice cooperation purposes within the domain of global public goods. Such cooperation is a rational response to globalisation, but faces several obstacles. These range from sociocultural and political concerns about national legal and criminal justice autonomy to the potential impact of market fundamentalism on scientific standardisation and cooperation mechanism delivery. The significance of such inhibitors will vary as societal and personal perceptions of stability change. These issues are examined by analysing the progress achieved with the EU Prüm forensic biometric data exchange model. Shocks to European stability, such as the increased scale of terrorist crimes and the UK EU referendum result will inevitably test the resilience of Prüm. Combining insights from global public goods and criminal law scholarship, however, may help to identify how reactions to such shocks, including questions about future UK participation in Prüm, might be managed.

Die Diskussion um die Weiterentwicklung der Belange der Offentlichen Gesundheit wurde durch die Stellungnahme der Leopoldina/Acatech/Union der Deutschen Akademien der Wissenschaften zu Public Health in Deutschland aus dem Jahr 2015 neu belebt. Die Stellungnahme spricht sich fur eine Starkung von Public Health und Global Health in Deutschland unter ausdrucklicher Einbeziehung des Offentlichen Gesundheitsdienstes (OGD) aus. Die unverzichtbare Einbeziehung des OGD in die Planungen bietet fur Public Health in Deutschland erstmals die Chance eines weitraumigen und nachhaltigen Praxis-/Politik-Transfers auf Bundes-, Landes- und kommunaler Ebene, auch als Grundlage fur supranationale europaische und internationale Partnerschaften. Fur den OGD bietet sich die Chance einer nachhaltigen Vernetzung mit modernen akademischen Public Health-Einrichtungen und die in der Bundesrepublik bisher fehlende Reprasentation des eigenen Fach(arztlichen)gebiets an den Universitaten. Ein Johann-Peter Frank Kooperationsmodell fur die gestufte Ausgestaltung dieses Ubergangs unter Einbeziehung der Akademien fur Offentliches Gesundheitswesen wird vorgestellt.

In 2012, the Framework Act on Cooperatives was legislated and about 7,500 co-operatives have been newly established in Korea. However, most of them are small, less competitive, and less skilled in management. In addition, they have difficulties in obtaining financial and management support from other organizations due to the lack of general awareness about co-operatives in Korea. To assist these co-operatives, secondary self-formed organizations composed of co-operatives have been created. This study explores the characteristics of these organizations and proposes possible models and strategies for cooperation among co-ops through these secondary organizations. In detail, we explore (1) the cooperation model to encourage collaboration among co-ops, (2) the roles and possibilities of secondary organizations to activate this cooperation model, and (3) the specific strategies and challenges for a more accessible cooperation model. To answer these questions, we conduct focus group and in-depth interviews with member and non-member co-ops in the Guro Community Association of Co-operatives, which is a self-organized secondary association in the Guro district in Seoul. Based on the interviews, we tried to find out their needs and the possibility for cooperation among co-ops at the level of the association. Also, we drew a conceptual cooperation model and its specific strategies through the association from theoretical review and interviews.

Based on the classic Lotlk-Volterra cooperation model, we establish a time-delay model of which a species cannot survive independently. By continuation theorem, we discuss existence of positive periodic solutions of the model.