An Empirical Analysis on DPRK: Will Grain Yield Influence Foreign Policy Tendency?

Democratic People’s Republic of Korea is the hub of Northeast Asia and its geopolitics is of great significance, whose foreign policy trend is not only related to the peace and stability of the region, but also one of the major variables affecting cooperation in Northeast Asia. According to the data on North Korea’s grain yield collected by the Korea National Statistical Office, supplemented by the data on international food aid to North Korea collected by the World Food Programme, and combined with the judgment of 10 experts from China, South Korea and the United States on the Hawk and Dove Index of North Korea’s foreign policy from 1990 to 2018, we use empirical mode decomposition wavelet transform data analysis and feature extraction methods to study the impact relationship, and OLS regression analysis to study the actual cycle of transformation. We found that: (1) North Korea’s grain output is an important indicator that affects its foreign policy tendency (hawks or doves). The hawk refers to those who take a tough attitude in policy and prefer rigid means such as containment, intimidation and conflicts; the dove refers to those who take mild attitude in policy, and prefer to adopt flexible means such as negotiation, cooperation, and coordination. When it comes to grain yield increase, North Korea’s foreign policy tends to be hawkish; when it comes to grain reduction, its dovish tendency will be on the rise. This is because food increase can alleviate grain shortage in North Korea and enhance its ability to adopt tough policies in its foreign policy. However, decreases in grain production will lead to adopt a more moderate policy and seek international cooperation and assistance to ease the internal pressure caused by grain shortage. (2) North Korea’s grain yield influencing its foreign policy (hawks or doves) has a lag phase of about 3 years. Such being the case, the accumulated grain during the production increase period has enhanced North Korea’s ability to cope with grain reduction in the short term. Secondly, the North Korean government blames the reduction on foreign sanctions, which will instead make the North Korean people more determined to resist external pressure. Therefore, we can use the changes in North Korea’s grain output to predict the direction of its foreign policy so as to more accurately judge the development of the Korean Peninsula and more effectively promote the process of peace and cooperation in Northeast Asia. We concluded that grain production will affect its policy sustainability in North Korea.


Introduction
Changes in a country's foreign policy will often have an impact on its region or even the international community to some degree. It is true that, similar to domestic policies, foreign policies will also be subject to factors such as the domestic political system, political tendency, and characteristics of leadership. However, foreign policies are more sustainable as objective national interests are their common fundamental basis [1]. Therefore, the sustainability of foreign policy refers to the principles, ideas, preferences and other factors that have long-term influence on a country's foreign policy. And countries with an important geographical position in particular, the relationship between the sustainability of their foreign policies and the stability of the regional geopolitical structure is particularly significant [2]. Therefore, measuring and predicting the sustainability of a specific country's foreign policy is not only related to the overall situation of regional political stability, but also of great significance to the sustainability of the development of international relations.
Located in the heart of Northeast Asia, bordered by China and Russia to the north, South Korea to the south, North Korea lies across the seas from Japan and China to the east and west. North Korea is not only a bridge between the mainland and the sea, but also the only way for Northeast Asian countries to realize connectivity. Therefore, its geographical location is of great significance [3]. At the same time, North Korea is also a relatively closed country isolated from the international community for a long time with limited contact with foreign countries. Moreover, its political structure presents the characteristics of "the only leadership system of the top leader" [4][5][6][7], in which the personal will and preferences of leaders have great influence on the formulation of national policies [8]. Therefore, it is likely that countries like North Korea will be major variables in this region, directly affecting the sustainability of regional development and a further influence on the liberalization of regional investment and trade.
Certainly, it does not mean that North Korea has no connection with the international community in spite of its relatively closed society. With the development of communication, transportation and information technology, we have seen many economies are inextricably linked to the global economy and the world is gradually becoming a "global village" [9]. Even though North Korea has limited contacts with the outside world, it still has interdependent relations with other countries and the international community。 During the Cold War, North Korea relied mainly on socialist countries in its foreign trade, followed by the third world countries, which began to develop trade with western countries except the United States in the 1980s [10].However, the end of the Cold War and the outbreak of the first North Korean nuclear crisis have sharply worsened the international environment facing North Korea and the foreign aid to the country significantly reduced. In addition, the rigid planned economic system is difficult to transform and the development of domestic industrial structure is unbalanced. Therefore, since the 1990s North Korea has encountered severe economic difficulties and the food shortage is particularly prominent [11].The main causes of food shortage in North Korea include aging and damaged agricultural infrastructure, frequent natural disasters, serious foreign exchange shortage, sanctions imposed by the international community and adherence to the planned economic system [12,13]. At the same time, from the perspective of consumption structure, grain (mainly rice and corn) is still the main source of food consumption in North Korea. Although North Korea has tried to develop alternative food sources by encouraging livestock breeding and developing aquaculture since the late 1990s, the proportion of these substitutes in food consumption is still very low [14].The food problem(Grain output) is the core issue of North Korea's domestic economy, and its influence on North Korea's politics is particularly significant.
Since the 1990s, many scholars on North Korea issues have shifted its focus to the importance of food issues and made unremitting explorations. Their researches mainly cover the following three aspects: First, the assessment of North Korea's food security. Though it is difficult to obtain official statistics, Woon Keun Kim and others have speculated about North Korea's food situation with the data of daily rations of grain per person across North Korea and the experimental data gained in South Korea by simulating the situation of North Korea to estimate the daily consumption and production of grain in North Korea respectively. As a result, they draw the conclusion that even in normal conditions, North Korea has serious food deficit of which the median amount can reach 12% of daily consumption [15,16]. But Randall Ireson holds different opinions. He believes that although the specific data on agricultural production is inaccessible, it is certain that North Korea will gradually achieve self-sufficiency in food with technology and material support [17].
Second, the analysis of North Korean food aid issue. Since the 1990s, the international community, including the United States, Japan, and China, has launched food aid projects out of humanitarian to ease the aggravation of the North Korean food crisis. According to the analysis of its effectiveness made by Stephan Haggard and Marcus Noland, these foods were not given to those in bad demand. Instead, it was transferred to Pyongyang residents and workers in key industries due to the lack of monitoring mechanisms and independent distribution channels. It is estimated that about 30% of these food is transferred by the North Korean government [18][19][20]. Li Nan retrospected the history of the United States' aids to North Korea, pointing out that the United States' food aid policy toward the North Korea is full of distinctive political characteristics. The United States aims to take food aid as a means to force North Korea to abandon its nuclear program and to further change its political and social systems. However, the facts have proved that it is difficult for North Korea to make substantive concessions on security, politics, and other issues merely based on food aid [21]. Meanwhile, scholars from South Korea prefer to promote the North-South cooperation with food aid projects. In Kwon Tae-Jin's opinion, such humanitarian acts can create nice environment for cooperation, and then promote the continued cooperation between the two countries in the agricultural field [22].
Third, the impact of the food issue on North Korea's internal affairs. Marcus Noland thinks that food shortage problem plays an important role in triggering North Korea's reform. By then, North Korea has changed some rigid economic systems through adjustments of micro and macroeconomic policies, the establishment of special economic zones, and the search for foreign aids, etc. But he also agrees that these reforms have limited effects as the North Korea's food production has not been restored and its people are still suffering from hungry [4]. Kang Yang-Hee calls North Korea's food problem "food politics" and argues that North Korea has increased public support for the regime by blaming food shortages on external pressures. Even though, Kang says such food policies will expose its limitations in consolidating the people's centripetal power towards the North Korean government with the increase of domestic personnel flow and information exchange in North Korea [23]. While Lim Sang-Cheol paid more attention to the impact of food shortages on North Korean society, including the rise of secret economic activities, the weakening of state control, the disintegration of families, undernourishment of adolescents, and citizens' increasing expectations of foreign countries [24].
The existed researches suggest that although there has been a lot of fruitful researches on the Korean food issue, there are still some shortcomings: first, few discussions focus on the relationship between the food issue and North Korean foreign policy, namely, how will food issue affect North Korea's diplomacy; second, these researches focus more on qualitative study but seldom apply quantitative methods. Therefore, this paper intends to systematically and quantitatively study the impact of food issues on North Korea's foreign policy through three methods: EOF decomposition, wavelet transform, and OLS estimation so that a more accurate judgment on the future foreign policy of North Korea might be made. What needs to be explained here is that although foreign policy is a term in a relatively broader sense, its contents include security policy, economic policy, etc. And the academic circles generally argue that the foreign policy is a clear or ambiguous act beyond the national boundary designed for government officials to promote the national interests, and the priority of this design characterized by integrity and macroscopical meaning constitutes the guidelines for the state to take actions to achieve its goals in a specific situation [25,26]. Therefore, the trend of North Korea's foreign policy mentioned in this paper refers to the basic attitude adopted by North Korea in dealing with foreign affairs.

Data
Starting from analyzing the grain output data and implementing the scientific criterion of hawk-dove score in a reasonable fashion, the paper aims to study the relationship between grain output and its foreign policy (hawks or doves) in North Korea. First of all, this paper collects the data of North Korea's grain output from 1990 to 2018 through North Korea Statistics Portal of Korea National Statistical Office [27].
In addition, in order to further understand the relationship between grain output and dove-hawk scores based on the fact that North Korea has received a large amount of international food aid, the paper sorts the data on international food aid to North Korea from 1995 to 2012 compiled by the United Nations Food Programme on North Korea in the World website (North Korea only began to receive international aid in 1995, and the statistics of the World Food Programme were interrupted in 2013 and beyond) [28].
Secondly, the author established statistical tables in judging North Korea's foreign policy (hawks or doves) from first arrange the historical events of great significance in North Korea's foreign relations from 1990 to 2018 in a way that we have invited 10 experts and scholars from China, South Korea and the United States in the field of Korean Peninsula to check what they think is of great importance, and made a Chronology of North Korean Foreign Affairs from 1990 to 2018. Then, scores were given by 10 experts on the policy tendency (hawks or doves) of each event and the average score was made to get the hawk-dove scores of North Korea's foreign policy during the period of time.

Empirical Orthogonal Function
Empirical orthogonal function (EOF) is a data reduction analysis method for spatio-temporal data [29][30][31], the principle of which is to decompose the original data observed n times by m variables into the product of time function and characteristic function according to the principle of variance maximization, thus reflecting the changes of the original data objectively and quantitatively: In the solution process, the original panel data is treated as an anomaly, and the eigenvalues and eigenvectors of the symmetric matrix are realistic, and the eigenfunction matrix V is constructed to further calculate the time coefficient matrix T: And the variance contribution rate of the feature vector and the cumulative variance contribution rate of the first feature vectors are calculated: It can carry out the significant test through calculating the error range of eigenvalues. When the adjacent eigenvalues and satisfy − ≥ ( ) , it is considered that the modes corresponding to the two eigenvalues have passed the significance test [32].

Wavelet Transform
Wavelet transform is an analysis method of signals based on time-frequency. It can characterize signals in time and frequency domains featuring multi resolution. After the wavelet transform shifts the basic wavelet by τ , it performs an inner product with the analytic signal at different scales a : This formula, > 0，which is called scale factor, is used to expand and contract the basic wavelet , ( ). can reflect the displacement. a and τ are continuous variables. Therefore, it is also called continuous wavelet transform. Complex Morlet wavelet is a single-frequency complex sine-modulated Gaussian wave, and it is also the most commonly used complex-valued wavelet, of which the time-frequency domain has good locality [33]. Therefore, this paper selects complex Morlet wavelet as the basic wavelet function and calculates it by using matlab2018b. Complex Morlet wavelet can be shown as follow： ( ) = ( × ) .

Multivariable Linear Regression
In order to explore the relationship between the policy tendency (hawks or doves) and the food condition, the factors reflecting the grain situation are used as independent variables to explain the changes in the policy tendency, based on which an multivariable linear regression model is established. Multiple linear regression is used to analyze the general relationship between two independent variable X and dependent variable Y, so as to determine the appropriate mathematical expression.
= + Note: ε represents the constant term, and c is the regression coefficients.

Discussions
Based on the above calculation results, this paper uses EOF decomposition to further analyze the relationship between North Korea's grain output and its foreign policy orientation. EOF decomposition is a method to extract the feature quantities of main data by using the interrelation among multiple variables to make a few new variables, which are independent of each other and can comprehensively reflect the information of the original multiple variables. EOF decomposes the original data into eigenvectors and time coefficients, and the former represents the characteristics of different variables, while the latter reflects the time variation trend.
The two significant modes can be obtained through EOF decomposition of five variables from 1990 to 2018 including dove-hawk transformation, hawk-dove scores, hawk-dove averages, grain yield and grain price rise and fall, with the cumulative variance contribution rate reaching 99.62%. And the contribution rate of variance of the first mode is 70.43%, which is much larger than that of other modes, indicating that the EOF decomposition result shown to be satisfactory., and the first mode is the main mode reflecting the five types of variables and is tested by North's Rule of Thumb. As shown in Table 1, the characteristic value of grain output is 0.9422, which is much larger than that of other variables, reflecting the most marked change of grain output from 1990 to 2018. In addition, the characteristic value of the first mode of hawk-dove scores is -0.3323, which indicates that the hawk-dove scores has a reverse change with the grain yield in the first mode, and itis slightly lower than the grain yield in the change extent (please refer to Appendix A). The time coefficient of a certain period is positive, which indicates that the variation of each variable in this period has a distribution similar to the obtained spatial type. If the time coefficient is negative, it is opposite to the obtained spatial type distribution. The larger the absolute value of the time coefficient value, the more typical the distribution pattern is. As can be seen from Figure 1, the first mode coefficient is relatively negative in 1995-1998, 2000 and 2007, which indicates that the grain output fluctuates briefly and violently in negative direction in these years. It is a fact that in 1995, North Korea suffered an unprecedented flood, which destroyed3.2 million hectares of rice and corn fields and lost about 900,000 tons of grain, amounting to 15 billion US dollars [34]. Subsequently, the floods in 1996 and the drought in 1997 further hit North Korea's agriculture, bringing North Korea into an era of so-called "Arduous March" [35]. It was not until 1999 that North Korea's grain output returned to normal in 1994. After entering the 21st century, although the food crisis in North Korea has improved somewhat, the impact of natural disasters on food production is still very great [36,37]. In 2007, North Korea once again experienced the worst rainstorm in 40 years, bringing the food quota for urban residents to an all-time low. After 2011, however, the time coefficients of the first mode are all positive, which means that the grain output under this mode has increased steadily. The time coefficient of the first mode shows a fluctuating upward trend, which is mainly due to the fact that North Korea has started to implement field responsibility system of taking on responsibility again since 2012. By allowing private contracted land management on the premise of ensuring sufficient public grain [38], the enthusiasm of farmers and the efficiency of agricultural production have been raised to a certain extent [39]. The time coefficient of the first mode is subjected to wavelet transformation, and the result is shown in Figure 2(a). It can be seen that there is a 4a periodic change from 1992 to 1998, and 4-6a since 1998, of which Figure 3(a) shows that the period of 6 years is the most significant. The contribution rate of variance of the second mode is 29.19%, and the characteristic value of hawk-dove scores of the second mode in Table 1 is 0.9350, which is much larger than the grain yield of 0.3350. Therefore, the second mode is mainly characterized by hawk-dove scores with the grain yield weaker changing with hawk-dove score. From the time coefficient of the second mode in Figure 1, it can be seen that from 1997 to 1998, 2007 to 2008 and in 2018, the grain output and hawk-dove scores showed relatively obvious synchronous growth, which indicates that while North Korea implements a relatively mild foreign policy, the grain is also increasing. According to the statistics of annual grain production in North Korea, turning points of grain production from negative to positive can be seen in the two periods of 1997~1998 and 2007~2008. At the same time, as North Korea was participating in the Four-Party Talks and the Six-Party Talks, it also preferred cooperation to confrontation in its foreign relations [40]. However, there were obvious negative changes in 1993, 1997, 2009, 2013 and in 2016-2017. In terms of grain output, two of the above years have increased production and three have decreased production. However, in terms of foreign policy, with the exception of 1997, North Korea has shown a very strong tendency toward its foreign policy. North Korea announced its withdrawal from Treaty on the Non-Proliferation of Nuclear Weapons for the first time in 1993, and then conducted its second nuclear test and withdrew from the Six-Party Talks in 2009. It conducted the third nuclear test in 2013 and three more nuclear tests in succession from 2016 to 2017, leaving the situation on the peninsula in a state of high tension. There is no obvious trend in the time coefficient of the second mode, but it can be seen from Figure  2(b) that after 2004, the time coefficient of the second mode has a period of 4 ~ 6a years. It can be seen that the period of 5 years is the most significant, followed by 6 years from observing the variance peak of the wavelet analysis in Figure 3 Due to the obvious synchronous relationship between hawk-dove scores and grain yield shown in EOF decomposition results, there are similar periodic changes, especially after 2004, it is more prominent between hawk-dove scores and grain yield of the synchronization and periodic similarity. Before 2004, the synchronous relationship between the two was not particularly prominent, mainly because the international community's food aid to North Korea weakened the impact of food production on hawk-dove scores. Since North Korea first made a public request for assistance to the international community in 1995, the World Food Programme and the United States, Japan, South Korea and China have all started food aid to North Korea [41]. According to the statistics of the World Food Programme, the amount of international food aid to North Korea remained high until 2005. In 2001, the international community's food aid to North Korea reached its peak, almost three times the amount of aid in 1995 [42]. This is mainly because the western countries led by the United States offering aid hope to intervene North Korea's politics to change the internal situation of North Korea [43,44]. Thanks to the supply of international aid, the food shortage in North Korea has been eased to a large extent, and the pressure of relying on domestic production for food supply has also been partially eased. However, the amount of food aid from the international community to North Korea has dropped significantly after 2005. The peak value of international food aid to North Korea, except for 2007, in other years is less than 70% of that in 1995, and the lowest value is even over 1/10 of that in 1995 [28]. This situation, on the one hand, is the deterioration of relations between North Korea and the United States and other major donor countries with the food aid linked to North Korea's human rights issues [45], resulting in North Korea's resistance to international aid. But on the other hand, more importantly, North Korea conducted its first nuclear test in 2006, which made the international community began to impose economic sanctions on North Korea and sharply cut its food aid. Therefore, North Korea has to rely more on self-reliance to address food shortage, so the impact of domestic food production on foreign policy (hawks or doves) is highlighted.  In order to further explore the relationship between the policy tendency (hawks or doves) and the food situation, a correlation analysis was made on the influencing factors of the two. At the same time, due to the lack of expression channels of policy needs, the self-interest features of policy subjects, the outdated policies which remained so for the limited rationality of decision makers, and the incapability of decision makers in integration and innovation [46], policies often fail to follow the social trends. Due to the hysteretic nature of the implementation of policy, the three-year average can better reflect the correlation between the hawk-dove index and grain production. According to Paarlberg Robert L's research, it takes some time to show the impact of food production on national policies [47]. And B. Habib's research also shows that food shortages have caused great pressure on North Korea's system, leading to policy changes several years later [48]. And from the regression analysis results, the three-year average has better significance. Therefore, the author calculated the three-year averages of the dove-hawk score and the grain output and the results of the correlation analysis are shown in Table 2.

Dove-Hawk Changes Dove-Hawk Scores Dove-Hawk Averages
Grain Output -0.48114*** -0.52145** -0.36466* Grain Output Changes -0.09399 -0.23279 -0.41347** ***, * * and * represent remarkable decline of significance level at 1%, 5% and 10% respectively As can be seen from the values in the table, there is a negative correlation between food output and policy tendency (doves or hawks). The correlation coefficient between the grain output and the dove-hawk score alone exceeds 0.5, which suggests they have a strong correlation. Therefore, further OLS regression analysis was carried out for grain output and the dove-hawk score.
= + ⋅ Here， represents the three-year averages of the dove-hawk score, the three-year averages of food output, c the Coefficient variable, ε the Error term.
Regression result: The observed value of the F-test statistic is 4.5443, and the corresponding probability p is 0.0073, which is less than 0.01. Accordingly, there maybe a linear relationship between the dove-hawk score and the grain output. The T-test probability p values of ε and 1 c are 0.0067 and 0.0073, both are less than 0.01. Therefore, the two regression coefficient is significant. The variable grain price rise and fall failed the significance test. Based on that, the linear regression equation can be created as: From formula (2), we can know that the grain output coefficient is -0.2073, namely, for each unit of grain production increase, the dove-hawk score will decrease by 0.2073, namely, the doves turns to hawkish. This means that increased grain production will make North Korea's foreign policy tougher. It is not difficult to understand. As North Korea suffers from the rigidity of the planned economic system, the sudden changes in the Soviet Union and Eastern Europe [49], as well as the frequent occurrence of natural disasters, its food security has been challenged since the 1990s. Food shortages have caused many instabilities in North Korea, leading to serious social problems [50,51]. In order to solve the food problem, North Korea has to adopt a relatively moderate policy on some foreign affairs, and strive for foreign aids and a good international environment. For example, the convening of the four-party talks in 1997 has a close relationship with the United States' provision of additional food aid to North Korea [52]. However, after the Cold War, the severe imbalance in Northeast Asia's strategic pattern triggered an unprecedented sense of insecurity in North Korea. Obtaining security thus becomes the primary goal of its regime [53]. To realize it, nuclear possession is an important means. Once the food shortage problem and domestic conflicts is settled, North Korea will turn its attention to nuclear weapons construction and take stronger protective action to ensure the security [54]. Therefore, the increase in grain output will ease North Korea and allow North Korea to resist the military pressure and economic sanctions imposed by the United States, South Korea and other countries with a relatively tough attitude.
In addition, from the regression analysis, there is a lag of about 3 years in the impact of grain output on dove-hawk score, namely, it will take about 3 years for policy changes, either the change in the policy from doves to hawks due to increased grain production or the change in policy from hawks to doves caused by reduced grain production, to show off. Because, at the beginning of the reduction of grain production, the previous increase in production will strengthen the government's ability to cope with domestic food shortages in the short term. At the same time, the government may consider the reduction in output as temporary which may soon improve. So, in short term, they don't think it is necessary to adjust policies. Second, the North Korean government often complains domestic economic difficulties on external sanctions and pressures, mobilizes nationalist sentiments. As a result, its citizens would rather insist on their national interests even at the cost of huge punishments [55], adding greater internal pressure to policy adjustment. However, as the reduction in production continues, the growing food gap will cause greater trouble for the government. The shortage of food will also stimulate social contradictions, forcing North Korea to consider adjusting its foreign policy. For example, the two consecutive catastrophes in 1995 and 1996 triggered the Four-Party Talks in 1997 and the improvement of US-DPRK relations to some extent around the turn of the century [31,56]. From 2010 to 2013, except for a slight reduction in food production in 2011, North Korea had a growing trend in food output. But this growth prompted four consecutive nuclear tests between 2013 and 2017 (so far, North Korea has only conducted a total of 6 nuclear tests).
Positively, since 2018, there have been some signals indicating the increasing possibility of denuclearization in the Korean Peninsula [57]. However, the process of North Korea's nuclear abandonment is full of variables. The U.S. and North Korea still cannot bridge each other especially when some substantive contents become topics of their negotiations [58,59]. As the domestic situation, especially the economy of North Korea is improving, it may resume the confrontation with the United States. Food controls the economy North Korea. According to the above research, North Korea's grain output can have an irreplaceable impact on its foreign policy. Therefore, we can prejudge the future policies that North Korea may adopt in the process of denuclearization based on its food production.

Conclusions
This paper uses EOF decomposition, wavelet transform and multivariable linear regression to analyze the relationship between North Korea's grain output and its foreign policy from 1990 to 2018 based on North Korea's grain output data and academic experts' scores on North Korea's foreign policy (hawks or doves). The following conclusions are drawn: 1. North Korea's grain output is one of the important indicators to predict its foreign policy tendency towards hawkish or dovish. When grain production increases, North Korea's foreign policy tends to be hawkish. When the grain output is reduced, the dovish tendency of North Korea's foreign policy will rise. 2. Due to the hysteretic nature of the grain output to its foreign policy tendency (hawks or doves), with a lag time of about three years, which means the increase in grain production will give rise to signs of hawkish tendency, while the decrease in grain production will trigger the return of dovish tendency three years later. 3. Currently, the Korean Peninsula is at a very critical moment with its extremely sensitive political situation. The uncertainties have also increased as a result of the impasse of the denuclearization negotiations with the United States. As North Korea's grain output is one of the important indicators for predicting its foreign policy tendency, we can judge the direction of North Korea's foreign policy based on the statistics of grain production, help promote North Korea and the United States to have peaceful negotiations, and effectively promote denuclearization of the Korean Peninsula. 4. North Korea's grain output can be taken as an important reference for predicting the choice of its foreign policy, which is an important determinant of whether Northeast Asia's regional cooperation can proceed smoothly. Therefore, we can use grain output to judge the stability and sustainability of Northeast Asia's regional relations and to advance effective development of economic activities such as trade and investment.

Conflicts of Interest:
The authors declare no conflict of interest.